I don’t own a hub motor myself and have never have tried it but from my understanding they inherently get hot because the urethane covers up the motor instead of leaving it exposed for cooling like outrunners. The design of the Maytech hubs seem to confirm this in that the heat is being trapped and when there’s heat in your coils there’s more resistance, slowing you down. Other mainstream hubs like Meepo are integrated with the truck and have cone shape on the truck side for cooling as well as the truck helping dissipate the heat. Plus they’re limited to 35kph/22mph and tested at the factory to perform within these limits.
Also check the windings of the motor, a lot of times these motors rushed in mass production in China and the windings themselves are done poorly causing inefficiency. If you have enough money to spare I would recommend buying @Hummie hub motors. He hand winds them himself and checks that it is getting the right kv and is made of steel instead of aluminum. If you can wait there is also Carvon direct drives which you can choose your own wheel but that is pretty much unavailable because its only 1 guy producing it and he’s produced 25 in 8 months.
If I were you just go with belt driven or wait a couple more weeks for @Kug3lis to offer geared driven “direct” drives. Honestly this where the next level tech is.
If you do decide to remain in the hub motor game but just not Maytech hubs. Raptor 2 offers hub motors but that’ll cost you $800 per hub because they don’t sell standalone hubs. You’ll have to buy the complete then take apart the hub. You will have the best hub motors in the industry imo.